The authors concluded that it was not possible to draw firm conclusions for the effectiveness of any surgical or injection-based intervention for patients with chronic whiplash-associated disorder. Despite the risk that relevant studies were missed and the review was prone to language and publication biases, the authors' cautious conclusions reflected the limited evidence presented and are probably reliable.

Authors' objectives

To assess the effectiveness of surgical and injection-based interventions initiated during the chronic phase of whiplash-associated disorder.

Searching

EMBASE, PubMed, CINAHL, PsycINFO, Cochrane Central Register of Controlled Trials (CENTRAL) and Web of Science were searched from January 1980 to March 2009 for English-language studies; search terms were reported.

Study selection

Clinical studies that included at least three participants aged at least 18 years of age with whiplash injury that evaluated the effectiveness of at least one clearly defined surgical or injection-based intervention for the chronic phase of whiplash-associated disorder were eligible for inclusion. The chronic phase was defined as more than 12 weeks post injury. Either a motor vehicle collision had to be responsible for whiplash-associated disorder in at least 60% of the study participants or motor vehicle collision-related whiplash patients had to form a distinct or separately analysed group of patients.

Study quality was assessed using the PEDro scoring system for RCTs using 10 criteria (maximum score 10). Scores of at least 9 were considered excellent quality, 6 to 8 were good quality studies, 4 to 5 were fair quality studies and scores less than 4 were poor quality studies.

Two reviewers independently assessed study quality; discrepancies were resolved through consensus or referral to a third reviewer.

Data extraction

Descriptive data were extracted on outcome measures and results.

The authors did not state how many reviewers extracted data.

Methods of synthesis

The authors conducted a narrative synthesis. Study details were tabulated and grouped by intervention.

Results of the review

Twenty-three studies were included in the review (n=679, range 10 to 66). Six studies were RCTs with high overall methodological quality (median PEDro score of 7.5, range 6 to 9). Allocation concealment was applied in four studies. Subject blinding was used in six studies. No studies undertook intention-to-treat analysis.

Injection-based interventions: Two RCTs of excellent quality found that botulinum A was not superior to placebo for reducing pain intensity at three or six months post treatment. For patients with chronic whiplash-associated disorder, corticosteroid intra-articular and selective nerve root block injections did not appear to be effective for pain relief (four studies; one RCT). Single case series for tropisetron trigger point injections, dextrose and lidocaine-articular injections and epidural blood patch therapy did not provide strong enough evidence to suggest that any of these interventions was effective for treatment of chronic whiplash-associated disorder.

Surgical interventions: There was some evidence (one RCT, two follow-up studies and five non-RCTs) that radiofrequency neurotomy iwas s effective in reducing pain in patients with chronic whiplash-associated disorder and that the procedure was repeatable, although pain relief may not be permanent. There was very limited evidence that occipital nerve decompression (one case series) and carpal tunnel decompression (one case series) were effective in reducing whiplash-related pain or headache. It was unclear whether cervical discectomy and fusion (two low-quality case series) offered relief for chronic whiplash-associated disorder patients.

Authors' conclusions

It was not possible to draw firm conclusions for the effectiveness of any surgical or injection-based intervention for patients with chronic whiplash-associated disorder. There were some positive results for radiofrequency neurotomy and mixed results for botulinum A.

CRD commentary

The review question was supported by appropriate inclusion criteria. Several electronic databases were searched. The search was restricted to English-language studies and this may have led to language bias. Limited searches were undertaken to identify unpublished studies; some relevant studies may have been missed. Quality assessment was undertaken in duplicate to minimise reviewer error and bias; it was unclear whether such methods were applied to study selection and data extraction. An appropriate checklist was used to assess the quality of RCTs. Given the differences between studies, a narrative synthesis was appropriate.

Despite the risk that relevant studies were missed and the review was prone to language and publication biases, the authors' cautious conclusions reflected the limited evidence presented and are probably reliable.

Implications of the review for practice and research

Practice: The authors did not state recommendations for practice.

Research: The authors stated that for further research was required to assess which interventions were most effective for patients with chronic whiplash-associated disorder refractory to conventional treatment.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.